Leu-Trp-Phe-Met-Ala-Ile-Val-   Draw the structure of the peptide at pH7.4.   and   Indicate the hydrogen bonds formed in the alpha helix.

Based on the pK, table for amino acids (Table 1.1), draw the structures with net charge, and the equilibria representing the complete deprotonation of aspartate. Table 1.1 Name pK pk2 pKR Glycine Alanine 2.4 9.8 2.3 9.7 Valine 2.3 2.4 9.6 Leucine 9.6 Isoleucine 2.4 9.7 Methionine 2.3 9.2 Phenylalanine Proline Serine 1.8 9.1 2.0 10.6 2.1 9.2 Threonine 2.6 10.4 Cysteine Asparagine Glutamine 1.8 10.8 8.3 2.0 8.8 2.2 9.1 Tyrosine Tryptophan Aspartate Glutamate 2.2 9.1 10.9 2.4 9.4 2.0 2.2 10.0 3.9 9.7 4.3 Histidine 1.8 9.2 6.0 10.8 Lysine Arginine 2.2 9.2 1.8 9.0 12.5

Draw the structure of the tri-peptide Leu-Asn-Ser  at pH 7.4. Use wedges and dashes around the alpha-carbons, and indicate charges where appropriate. Indicate which amino acid(s) has an R group that would avoid water.

1. Consider the following α helix from myoglobin at pH 7. Gln-Gly-Ala-Met-Asn-Lys-Ala-Leu-Glu-His-Phe-Arg-Lys-Asp-Ile-Ala-Ala-Lys-Tyr(a) Label amino acids in the polypeptide above as follows: p for polar and uncharged, np for non polar, – for negatively charged, and + for positively charged.(b) How many complete turns are there in this helix?(b) Which side chains are likely to be on the side of the helix that faces the aqueous solvent? Why?(c) Which side chains are likely to face the interior of the protein? Why?